1. Field of the Invention
The invention relates to filament member for a skirt for an air cushion vehicle which has beneath the bottom of the vehicle hull a number of air cushion chambers which are delimited in horizontal direction by the skirt and into which air supply means may blow air for maintaining the air cushion in the air cushion chamber during operation of the vehicle, the skirt including elongated, downwards extending filaments.
2. Description of the Prior Art
A skirt for an air cushion vehicle is known from the U.S. Pat. Nos. 3,249,167 and 3,172,494 showing skirts with brushes in the form of rods, wires, cords, chains or filaments made of plastic.
Another skirt is known from SE-B-305812, where skirt members are hanging down from the hull. The flexible skirt members are shaped with large cross-sections merging into each other such as triangular cross-sections with the apex facing alternatively inwards and outwards. These skirt members are not of the filament type.
The skirt extends along the periphery of the air cushion chambers and serves to prevent the air from freely escaping the chambers. In the traditional air cushion vehicles the skirt is constructed from a continuous rubber sheet, but such a sheet is frequently exposed to damage when the air cushion vehicle crosses obstacles which may seize the skirt.
A skirt of brushes as known from the above U.S.A.-patents possess the advantage that obstacles may pass freely through the brushes without damaging these.
It is a well known problem of air cushion vehicles that they hardly can be used in waters where there is risk of icing up because the ice is easily formed on the skirt and impedes the correct functioning thereof. This problem is especially distinct by the brushformed skirts having a very large surface area compared to the length of the skirt. As air cushion vehicles are very sensitive to weight changes even smaller deposits of ice on the skirt may demand suspension of the vehicle operation.
The object of the invention is to provide a skirt more appropriate for navigation in cold waters.
With this aim the filament member according to the invention is characterized in that the filament member has an upper base portion with engagement means for the attachment of the member to a retainer, and that the member includes several juxtaposed elongated filaments extending from the base portion and having less cross-sectional area at the free end of the filaments than at the root thereof. Such a member may in a simple manner be manufactured from a plastics material by means of injection moulding and it provides for assembling a skirt having any desired length simply by placing in the retainer a number of members corresponding to the desired skirt length. As each member only comprises comparatively few filaments such a skirt is repairable at low-costs in the event of skirt damages, because only the damaged members are to be replaced.